Code No. P0152: Left Bank Oxygen Sensor (Front) Circuit High Voltage

OPERATION

• The sensor signal is inputted to the engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 108) from the left bank oxygen sensor (front) output terminal (terminal No. 4).
  
• The left bank oxygen sensor (front) (terminal No. 2) is earthed with engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 96).
  

FUNCTION

• The left bank oxygen sensor (front) converts the concentration of oxygen in the exhaust emission into a voltage and inputs the signal to the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
  
• When the air-fuel ratio is richer than the theoretical air-fuel ratio, the left bank oxygen sensor (front) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V.
  
• In response to the signal, the engine-ECU <M/T> or engine-A/T-ECU <A/T> controls the fuel injection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.
  

TROUBLE JUDGMENT

• Above 2 seconds later after the engine has started up.
  

• Left bank oxygen sensor (front) output voltage is 1.2 V or more for 2 seconds.
  

PROBABLE CAUSES

• Short circuit in left bank oxygen sensor (front) circuit or loose connector contact
  
• Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>
  

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2 .

	Go to Step 3 .

	Repair or replace the connector.

	Go to Step 4 .

	Repair or replace the connector.

	Go to Step 5 .

	Repair the damaged harness wire.

	Go to Step 6 .

	Repair the damaged harness wire.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.